The present invention relates to a filter construction and to a method for making a filter construction.
Hard disk drives are enclosures in which an inflexible platter or disk coated with magnetic material is spun very rapidly. A magnetic read/write head xe2x80x9cfliesxe2x80x9d only a few microns above the disk on an air cushion. The efficiency of a hard disk drive is related, in part, to the distance between the head and the disk. Thus, it is desirable to position the head as close to the disk as possible without having the head touch the disk.
Particulate and gaseous contaminants present within the disk drive can reduce the efficiency and longevity of the hard disk drive. Common sources of contaminants in disk drives include air leaks in the drive enclosure (which may or may not be intentional), the manufacturing environment, and the materials incorporated into the disk drive that give off particulates and gases. It is of particular concern that organic vapors can be generated inside disk drive enclosures during normal operating conditions when, for example, the temperature exceeds 150xc2x0 F. (about 65xc2x0 C.). Such temperatures can be achieved by simply leaving a computer containing a hard drive in the trunk of a car on a hot day.
Various filters have been used in disk drives for removing chemical and particulate contaminates. One type or group of filters includes recirculation filters, which are often positioned in the path of air currents in the disk drive enclosure to remove or reduce contaminants from the air present within the disk drive enclosure. These filters remove particulate and/or chemical contaminants from the circulating air. Another type or group of filters includes breather filters, which are used to remove or reduce contaminants from air entering the disk drive enclosure. Generally, breather filters cover a port in the drive enclosure that is open to air flow communication with the exterior of the enclosure. This port is typically positioned in a low static pressure area so that the pressure outside of the enclosure is greater than inside at the port position. Positioning of the port in a low static pressure area provides positive air flow from the exterior of the enclosure to the interior. The areas of lowest static pressure are located directly above and below the rotation point of disk.
What is desired is a new filter construction for use with disk drives.
The present invention is directed to a filter construction for use in a disk drive enclosure. One feature of the filter construction of the present invention is that rather than being positioned above or below the disk, the filter construction can be positioned at an outer or peripheral edge of the disk. The outlet from the filter construction, referred to as the mouth, is positioned in a low static pressure area created by the spinning disk; the outlet is not necessarily in the lowest static pressure area, but is merely within a low static pressure area. In certain embodiments, the mouth is approximately parallel to the edge of the spinning disk so that air passing through the filter construction and exiting via the mouth is approximately perpendicular to the air circulated by disk. The mouth may be concave, mirroring the shape of the disk.
The invention includes filter constructions for use in disk drive enclosures that contain a disk drive assembly. The filter construction includes a housing defining an air inlet and an air outlet; an adsorbent filter element positioned within the housing and in fluid communication with the air inlet and the air outlet, the adsorbent filter element positioned to filter air entering the drive assembly; and a recirculation filter element positioned to filter air circulating within the drive assembly. The filter is generally configured for placement in a disk drive assembly containing a rotating disk, and the air inlet of the housing is positioned farther from the center of the rotating disk than the air outlet.
In certain implementations the air inlet is configured for positioning outside an edge of the rotating disk and the air outlet is configured for positioning closer to the center of the disk, such as inside the edge of the rotating disk. The air inlet can be configured for positioning outside of an edge of the rotating disk by a distance of at least 0.1 times radius of the rotating disk, alternatively the air inlet can be configured for positioning outside of an edge of the rotating disk by a distance of at least 0.25 times the radius of the rotating disk.
In one particular aspect, the invention is directed to a filter construction that has a first filter portion and a second filter portion in a housing. The first filter portion performs breather functions while the second filter portion provides recirculation functions. The first filter portion has an inlet that is configured and arranged to provide a path for flow of air into a disk drive enclosure. Generally, the inlet covers or surrounds the port leading into the drive enclosure. The flow of air enters the disk drive enclosure through the inlet and exits the first filter portion through the mouth. The first filter portion generally includes a diffusion channel in fluid communication with the inlet and with the mouth. The diffusion channel helps slow the transfer of air into and out of the drive enclosure. The second filter portion includes a recirculation filter configured and arranged to provide a path for flow of air within the disk drive enclosure, the flow of air passing through the second filter portion.
In another particular aspect, the present invention is directed to a disk drive assembly having a disk drive enclosure and a disk positioned within the enclosure. The enclosure has an air port extending through the enclosure, and a filter construction positioned within the enclosure. The filter construction is in fluid communication with the port and includes a first filter portion and a second filter portion. The first filter portion is configured and arranged for positioning in an air stream to provide a path for the flow of air into the disk drive enclosure. Air enters the disk drive enclosure through a port, passes through the first filter portion, and then exits the first filter portion through a mouth. The second filter portion is configured and arranged for positioning in an air current in the disk drive enclosure to provide a path for flow of air within the enclosure. When the disk is spinning, the disk drive enclosure has at least one low static pressure area, and the mouth is positioned in the low static pressure area of the disk drive enclosure.
A further aspect of the invention is directed to a filter construction for use in a disk drive assembly. The filter construction includes a housing configured for placement in a disk drive assembly containing a rotating disk. The housing contains an air inlet and an air outlet; the air inlet of the housing configured to be positioned farther from the center of the rotating disk than the air outlet. The housing also contains an air scoop and a channel connecting the air scoop with the air outlet; wherein the air scoop contains an opening that is positioned at an angle to the edge of the rotating disk that promotes entry of air into the scoop.
Generally this angle between the edge of the rotating disk and the scoop is greater than zero degrees but less than a right angle. Typically the angle is greater than fifteen degrees but less than 60 degrees. Suitable angles include, for example, approximately 30 to 60 degrees. The air scoop may be substantially perpendicular to the edge of the rotating disk while the air outlet is substantially parallel to the edge of the rotating disk. Such angles benefit from the general rotation of airflow through the disk drive assembly and are meant to capture a large portion of the airflow as it moves past the filter assembly. The filter construction includes an adsorbent filter element positioned within the housing and in fluid communication with the air inlet and the air outlet, the adsorbent filter element positioned to filter air entering the drive assembly.
The filter construction also includes a recirculation filter element positioned in the air channel between the air scoop and the air outlet to filter air circulating within the drive assembly; wherein the recirculation filter has a width exposed to air passing through the air channel, and the recirculation filter is positioned in the air channel so that the exposed width is greater than the air channel width at the recirculation filter position.